吡嗪酰胺在两种混合溶剂中的溶解度测定、关联与共溶剂现象

Solubility measurements, correlation and cosolvent phenomena for pyrazinamide in two mixed solvents

通过激光动态法测定了常压下吡嗪酰胺在甲醇+水和丙酮+正丙醇两种混合溶剂中、温度范围为283.15～323.15 K间的溶解度,并使用修正的Apelblat方程、λh方程、一般共存模型和修正后的Jouyban-Acree方程对实验数据进行了关联,其中Apelblat方程的关联效果最好。吡嗪酰胺在两种混合溶剂中的溶解度都随着温度的升高而增大,并且都出现了共溶剂现象,即当甲醇或丙酮的初始摩尔分数为0.6时,吡嗪酰胺的溶解度最大。另外使用van't Hoff方程计算了溶解过程的热力学性质,包括Gibbs自由能、焓变和熵变,证明了该溶解过程为吸热过程。通过得到的非线性焓-熵补偿图可知,溶解过程机理与共溶剂混合物的组成有关。

The solubility of pyrazinamide in methanol+water and acetone + n-propanol has been measured by a laser dynamic method in the temperature range between 283.15 and 323.15 K under normal pressure.The modified Apelblat equation and λh equation,the general coexistence model and the modified Jouyban-Acree equation were used to model the experimental data;it was found that the Apelblat equation showed the best correlation effect.The solubility of pyrazinamide in both mixed solvents increases with increasing temperature,and a cosolvent phenomenon occurs,that is,when the molar fraction of methanol or acetone is 0.6,the solubility of pyrazinamide is the largest.In addition,the thermodynamic properties of the dissolution process,including Gibbs free energy,enthalpy change and entropy change,were calculated using the van’t Hoff equation.The results demonstrate that the dissolution process is endothermic.From the obtained nonlinear enthalpy-entropy compensation map,the mechanism of the dissolution can be related to the composition of the cosolvent mixture.